Find `sum_(k=1)^ntan^(- 1)(2k)/(2+k^2+k^4)`

Find sum_(k=1)^(n)(tan^(-1)(2k))/(2+k^(2)+k^(4))

If sum_(k=1)^(k=n)(tan^(-1)(2k))/(2+k^(2)+k^(4))=tan^(-1)((6)/(7)), then the value of ' 'n' is equal to

sum_(k=1)^(2n+1)(-1)^(k-1)k^(2)=

Find the sum sum_(k=1) (""^nC_(2k-1))/(2k)

If for n in N,sum_(k=0)^(2n)(-1)^(k)(2nC_(k))^(2)=A, then find the value of sum_(k=0)^(2n)(-1)^(k)(k-2n)(2nC_(k))^(2)

Find the sum_(k=1)^(oo) sum_(n=1)^(oo)k/(2^(n+k)) .

Let S_(n)=sum_(k=1)^(4n)(-1)^((k(k+1))/2)k^(2) . Then S_(n) can take values